The present invention generally relates to electrical connection boxes and more particularly, to an electrical connection box in which a circuit formed by bus bars and a circuit formed by wires and pressing contact terminals connected to the wires can be installed reasonably.
In an electrical connection box used for connecting wiring harnesses or the like for a motor vehicle to various electric devices through branching, a branching connection point is concentrated at one spot such that branching connection of wires is performed reasonably and economically. In response to recent trends towards higher density of wiring harnesses, various types of electrical connection boxes have been developed for different models of motor vehicles and for different applications.
FIG. 1 shows one example of such known electrical connection boxes. The known electrical connection box includes an upper casing 1, a lower casing 2 and an insulating plate 3 provided in the upper and lower casings 1 and 2. A circuit formed by flat bus bars 4 is disposed on one face 3a of the insulating plate 3 adjacent to the upper casing 1, while a circuit formed by a number of single-conductor wires 5 is disposed in a space S defined between the other face 3b of the insulating plate 3 adjacent to the lower casing 3 and an inner face of the lower casing 2.
The circuit formed by the flat bus bars 4 and the circuit formed by the single-conductor wires 5 are employed as an internal circuit of the electrical connection box for the following reason. Namely, a load circuit which is subjected to design changes relatively frequently is constituted by the single-conductor wires 5 and pressing contact terminals (not shown) such that it becomes possible to easily cope with design changes of the load circuit.
However, usually, the circuit formed by the flat bus bars 4 and the circuit formed by the single-conductor wires 5 occupy 20% and 80% of the internal circuit of the electrical connection box, respectively. Therefore, since the circuit formed by the single-conductor wires 5 is far more than the circuit formed by the flat bus bars 4, the circuit formed by the single-conductor wires 5 is concentrated in the space S extraordinarily. As a result, such problems arise that productivity of the known electrical connection box deteriorates due to complication of laying of the single-conductor wires 5 and the known electrical connection box becomes larger in size owing to increase of its height H.